Conventional light systems, used for vehicle head lights or tail lights, typically use a bulb and reflector system. In a bulb and reflector system, the filament of the bulb is placed at or near a focal point of a parabolic reflector. The light emitted by the bulb filament is collected by the reflector and reflected outward to form a light beam. A lens may be used to shape the light beam into a specified pattern.
The conventional bulb and reflector systems have several disadvantages. For example, bulb and reflector systems collect and often reflect only thirty percent of the light emitted from the bulb filament into the useful lighting area. Additionally, thermal energy given off by the bulb during operation must be considered. The size of the reflector as well as the material used in its construction vary depending upon the amount of thermal energy generated by the bulb filament. Decreasing the size of the reflector requires use of materials with high thermal resistivity for the reflector. Further, bulb and reflector systems have disadvantages related to aerodynamics and aesthetics. For example, the depth of the reflector along its focal axis and the height of the reflector in directions perpendicular to the focal axis greatly limit attempts at streamlining vehicle contours.
An approach to develop an automotive lighting system directed at remedying the above disadvantages and for use with the newer streamlined vehicle contours is proposed in U.S. Pat. No. 5,434,754, assigned to the assignee of the present invention. Therein disclosed is the combination of a fiber optic light guide which transmits light from a remote light source, to a parabolic reflector, through a light manifold, and to a thin sheet optical element. The light guide is optically connected to the remote light source, the optical element, and sometimes to other light guides.
Certain advancements to such an approach have been directed at reducing the thickness of the thin sheet optical element. One way of accomplishing this reduction is by utilizing a high brightness remote light source. One approach is to provide a remote diode laser light source in combination with reduced diameter fiber optic light guides and reduced thickness optical elements. U.S. application Ser. No. 08/780,034, assigned to the assignee of the present invention, is exemplary of such an approach.
Utilization of a light management system as described will necessarily require system assembly and maintenance. The fiber optic light guides will need to be connected to the remote diode laser source, the thin sheet optical element, and potentially to other light guides. Further, the fiber optic light guides may deteriorate over time and may need to be disconnected and replaced. During such procedures the escape of laser light at the connection points is a condition to be avoided.
It is therefore desirable, particularly when using diode laser remote lighting systems, to provide for prevention of emission of laser light at the connection points, especially during system assembly or maintenance.